Cartridge magazine with elliptical springs



Jung 1!), 1962 D- D. MUSGRAVE CARTRIDGE MAGAZINE WITH ELLIPTICAL SPRINGS Filed March 6, 1961 United States Patent 3,039,221 CARTRIDGE MAGAZINE WITH ELLIPTICAL SPRINGS Daniel D. Musgrave, 8201 Caraway St., Cabin John, Md. Filed Mar. 6, 1961, Ser. No. 93,745 3 Claims. (Cl. 42-50) This invention relates to cartridge magazines for firearms wherein the successive rounds of ammunition are moved to a feeding position by the action of a springloaded follower. 'Such magazines may be divided into two general types according to the relative arrangement of the cartridges, which may be side-by-side or end-toend. The side-by-side arrangement is commonly referred to as the box type, and the end-to-end arrangement is usually known as the tubular magazine. For military use, the box magazine has become the dominant type and this invention will be disclosed as applied to a box magazine, but it could be applied to tubular magazines. (In this application the term magazine, alone, should be construed to mean a box magazine.)

Current practice is to make the magazine a self-contained unit which may be easily attached to or detached from the Weapon by the user. Each Weapon is usually accompanied by a plurality of magazines, so that the firer may replace an expended magazine with a full one, and resume firing with a minimum elapsed time for reloading the piece. Magazines of this general type have been in use for many years and have been developed to a high standard of functional reliability. But an important limitation for which allowance must be made is the tendency of the magazine spring to lose its resilience if stored under load for long periods of time. For this reason magazines are stored empty and loaded only when use appears imminent. This procedure requires separate and additional handling and packaging of the ammunition and the magazine which occupy more space in transit and in storage. It also requires that loading be accomplished in the lowerechelons of a supply system. This is contrary to present-day doctrine of relieving the ultimate user group of any supply activities which can better be performed in a higher echelon, such as a factory for fabricating magazines. It is apparent that loading of magazines can be accomplished more readily in a factory than in the field, Where the ultimate user may operate under severe environmental conditions. It is also apparent that loading in the field requires opening the protective packaging and that factory-loaded magazines could remain in their protective package when issued to the ultimate user group but for the limitation on the life of the springs.

In consideration of the aforementioned situation, the principal object of this invention is to provide a cartridge magazine which may remain in the loaded condition for long periods without its springs being adversely affected.

A further objection of this invention is to provide such a magazine which will be compatible with firearms presently in use as well as with those to be constructed in the future.

Another object is to provide a magazine which may be prepared for use by the weapon operator in a minimum time after removal from storage.

Another object is to provide a magazine which is reusable and may easily be prepared for long term storage after reloading.

These and other objects of the present invention will become more apparent upon reference to the following specification, taken in connection with the accompanying drawings, wherein:

FIGURE 1 is a side elevation, partly-sectioned, of a =box magazine having a cartridge lifting spring assembly which embodies the present invention.

3,039,221 Patented June 19, 1962 FIGURE 2 is a longitudinal section taken in the plane 22 on FIGURE 1.

FIGURE 3 is a partial transverse section taken in the plane 33 on FIGURE 2.

FIGURE 4 is a partial, perspective view of an elliptical, tubular spring.

FIGURE 5 is a partial perspective view of the cartridge lifting leaf spring in its free state when removed from the magazine assembly.

FIGURE 6 is a section of the leaf spring shown in FIGURE 5 with elliptical, tubular springs inserted in the vertices.

FIGURE 7 is similar to FIGURE 6, with the exception that the elliptical, tubular springs are oriented dilierently.

FIGURE 8 is similar to FIGURE 7, with the exception that the leaf spring is extended.

Referring to the drawings, there is shown in FIGURES 1, 2, and 3, a cartridge magazine having a casing 12, of substantially rectangular form, with ends 16, sides 17, and bottom 14. Casing 12 may be fabricated of any suitable material such as plastic or sheetmetal. As may be noted in FIGURE 1, conventional magazine lips 19 are formed at the upper or feeding end of casing 12.

Within casing 12 is disposed a typical cartridge follower 28 acting against the lowest cartridge 133, and second lowest cartridge 134 of the staggered rows to be advanced to the feeding position, which is indicated by the location of cartridge 34 in FIGURE '1. Grooves 3S and 40 in sidewalls 17 of casing 12 are used as stiifeners for casing 12 and as interior ribs to assist in properly aligning the rows of cartridges in the well-known manner.

Means are provided for removable attachment of casing 12 to the firearm so that the feeding position at lips 19 is substantially parallel to the main axis of the firearm.

Disposed in casing 12, between follower 28 and bottom 14, is a cartridge lifting spring assembly consisting of a folded leaf spring 21 and one or more elliptical tubular springs 24. The general arrangement of the spring assembly is shown in FIGURES l, 2, and 3.

FIGURE 4 shows ellipse spring '24 in detail. It may be fabricated of any suitable resilient material, such as spring steel. Its major axis is indicated by line XX and its minor axis by line YY. Suitably afiixed to one end of spring 24, as by weld 10, is lever arm 25, which is adapted to rotate spring 24 around its longitudinal axis, as will be described later. The assembly shown in FIGURE 4 can, of course, be fabricated opposite hand, to suit conditions.

FIGURE 5 shows a portion of a folded leaf spring 21 in its free or no-load state, before insertion of ellipse springs 24. Leaf spring 21 has at each fold, vertices 22, which, as may be noted in FIGURE 6, comprise a portion of an ellipse having its major axis oriented substantially parallel to the fiat portions of leaf spring 21. At the minor axis of the incomplete ellipse are formed detent grooves 23, the purpose of which will be explained later.

In FIGURE 6, it will be noted that ellipse springs 24 have been inserted into vertices 22. The dimensions of these parts are so chosen that ellipse springs 24 fit snugly into vertices 22 when their axes are similarly aligned, as shown in FIGURE 6. When the dimensions are so se lected, the insertion of the ellipse springs into the vertices will cause no significant torsion of leaf spring 21.

In FIGURE 7, ellipse springs 24 have been rotated thus aligning their major axes with detents 23 and torsioning leaf spring 21. The torsion of the leaf springs exerts a pincer effect at detents 23 thus firmly gripping ellipse springs 24 and retaining them in the position shown.

Another eifect of the torsion of leaf spring 21 as shown in FIGURE 7 is a tendency for the spring to expand between adjacent vertices in an effort to achieve the no-load ellipse spring 24 along its major axis can be utilized to store energy. I I I The installation of a spring assembly (as shown in I i FIGURE'6). into casing 12, will be understood by refer- I ence to FIGURES 1,2; and 3.1 'Inithe bottom 14 ofcasing 12, there is formed a slot 15through which protrudes a I I i slotted plate 27 having a pullcord 31 attached to the protruding portion. Formed-in plate'27 is slot 29 intov which lever arms of ellipse springs 24 extend when. the'spring I and plate are assembled. It will be noted that lever arms 25 are angled slightly'upwar'dand that the topmost ofthe levers is touching the top 260i slot 29 in plate 27 and thus is retaining the plate in position.

In the upper part of casingllis located follower 28 and the staggered rows of cartridges Dimensions of the sevieral components may be chosen so that the spring assembly; when installed as shown in FIGURE. 1', exerts aslight thrust between bottom 14 and follower 28, to holdthe rows of'cartridges intact.

Operation.The magazine shown in. FIGURE 1 is in I the loaded and stored condition; The condition of its springs is shown on a larger scale in FIGURE '6. Plate .27 with pullcord 31 attached is protruding from the bottom i of the magazine, and serves as an indicator thatthe springs I are inactive.

When'the user desiresto 'activateithe magazine he pulls,

, example, the vertices of the leaf spring may be staggered I Pyramided to permit the, assembly, tobemadesmaller and other methods may beemployedto attach the levers:

to the ellipse springs to assure maximum resiliency of the.

latter. I

What I claim is: 1. A magazine for a firearm comprising a case for stor-- :ing cartridges having a pair of lips with an exit port therebetween, a follower for engaging said cartridges, aIfolded I I I I leaf spring for engaging said follower and consisting of flat portions and partialielliptical portions, tubular elliptical springs inserted in said. partial elliptical portions I I I I I I with the major axes of said tubular elliptical springs co- I inciding with the major. axes of saidpartial elliptical portions, means for rotating said tubular elliptical springs to I I align their said major axes with the minor axes of said partial elliptical portions, and detent means .for retaining said major axes of said tubular elliptical: springs in align-I ment with said minor axes of said partial elliptical portions.

2. A magazine for a firearm comprising: a case for g I storing cartridges having a pair of lips with an exit port -therebetweenga follower for engaging said cartridges;

a spring for engaging said follower andhaving aplurality of pairs of longitudinal resilient portions and partial elliptical resilient portions therebetwecn, the major axes of said partialelliptical resilient portions being :in planes intermediate the respective planes of said longitudinal plate 27 out through slot 15 by means of pul'lcord 31 and plate 27 is discarded. Movement of the plate causes top 26 of slot 29 toco'ntactlever arms ZS and successively rotate ellipse springs 24 a quarterturn. The spring assembly I now has assumed the state shown in FIGURE 7 with the assembly tending to expand substantially. at right angles.

I tial elliptical resilient portions areincreased ordccreased to the flat portions of. leaf spring 21. I The spring there-I i f 'foreexerts a driving force on follower 28.

I As' cartridges are removed from the magazine during firing the spring assembly will take the shape shown in FIGURE 8.

It is desired to point out that changes may be made without departing from the spirit of the invention. For

'Iresilientportions; tubular elliptical members, inserted in said partial elliptical resilient portions, with the major 1 axes of said members coinciding with the major axes of I'said partial elliptical resilient portions; and means for axially rotating said members relative tosaid partial elliptical resilient portions, whereby the minor axes of said parto vary the resilience of saidspring. I I I I 3. The combination set forth in claim 2 and further I I characterized .by' the sections ofv said partial elliptical resilientportions at the minor axes thereof having indents I in the inner surface thereof for resiliently engaging the portions of said members near the major axes thereof.

No references cited. 

